The present invention relates to building blocks and more particularly to a novel modular building block for constructing masonry walls from a plurality of modular blocks.
In the past, conventional walls made of building blocks including concrete blocks and bricks have been constructed by locating one row of blocks on top of another row of blocks with a suitable bed of mortar therebetween. Leveling of such rows has the disadvantage of requiring the considerable skills of a mason in placing a suitable mortar bed and placing and tamping the blocks to provide a horizontal row typically with the assistance of a substantially horizontal stringline. Skill is required to ensure that mortar joints are provided having between a minimum and maximum thicknesses as is required under building codes and necessary for the wall to have acceptable strength. Variances in the mortar consistency create difficulties in maintaining proper mortar joint thickness. Conventional brick and block laying techniques are time consuming and expensive.
Conventionally laid block-and-mortar walls suffer the disadvantage that with the thickness of the mortar joint between blocks left to the skill of the mason, the effective vertical dimension of any course will vary. Typical building codes permit variances of joint thickness plus or minus 1/8 inch. To locate courses at suitable heights for openings for doors, windows or ceiling locations it is conventional to vary joint thickness notwithstanding that the ideal strength of the wall is thereby somewhat impaired. With conventional wall construction the placement and location of the horizontal joints between blocks cannot be accurately predicted as, for example, would be advantageous to permit precise prefabrication of modular wall covering panels with preplaced anchors or ties to be embedded into horizontal mortar joints of the wall.
Conventionally laid block and brick walls suffer the disadvantages that as only the mortar between the blocks supports an uncured mortar-block wall, only a given number of rows can be laid at any one time and an uncured wall lacks substantial structural stability. Thus masons must wait for wet mortar to partially cure before laying additional rows and plumbers and other sub-tradesmen cannot lay and connect their fittings and related connections in view of the risk of the freshly laid wall sagging or collapsing.
Various proposals have been made to stack conventional blocks in abutting relation with each other to form walls. Abuttment of conventional blocks has major disadvantages. Firstly walls made of blocks are subject to considerable forces due to contraction and expansion of the wall in view of changes in temperature and changes in water content of the blocks (hydration). In walls made from conventional blocks in abutting relation, the blocks are unable to withstand localized forces which become focused on particular points. Walls made from abutting conventional blocks typically will fail due to cracking and crumbling of the blocks.
Another major problem with blocks which are stacked in abutting relation arises in climates where the wall may be exposed to freezing temperature. In such climates, some means must be provided to resist water penetrating into the wall and particularly to prevent water from accumulating between abutting portions of the blocks.